1 Field of the Invention
The present invention relates generally to embroidering systems, and more particularly to a system for creating and modifying embroidery designs in either outline or stitch data format.
2. Description of the Prior Art
Systems to stitch embroidered lettering on articles are commonly known. Typically, embroidered lettering is described in terms of the stitch movements needed to control a stitching machine for reproducing lettering. In traditional prior art systems, embroidery characters are stored in a stitch-by-stitch format, in which each stitch and all needle-control data which were needed to recreate the embroidery design on the embroidery machine were stored.
Embroidery machines are generally controlled by programs, with a separate program required for each embroidery design. There are very few methods available which provide the ability to modify existing embroidery design programs. Methods that are available for modifying existing embroidery design programs are extremely limited. Prior methods for editing embroidery design programs have primarily been limited to increasing or decreasing the size of a pattern, varying stitch densities, changing the orientation of a design, producing a mirror image of a design, and varying fill, running, jump and satin stitch lengths. Furthermore, since all such prior art systems operate only on low level stitch data, they require that the voluminous stitch data be loaded into memory before any manipulation of the embroidery pattern may be done, and consequently that each individual stitch point be transformed during the manipulation process. This increases the processing time and memory requirements for such prior art systems.
Examples of such prior art systems for varying the parameters associated with a stitch pattern design in order to control stitching machinery, such as an embroidery machine or a sewing machine, are disclosed in Pongrass et al., U.S. Pat. No. 4,821,662 and Kinoshita et al., U.S. Pat. No. 4,720,795. These prior art methods, however, are limited in their editing capability and, for example, provide no means for converting straight line portions of a design pattern to smoothed curves, nor do they provide a means for converting a portion or all of the stitching in a design from one type of stitching, such as satin or tatami, to a different type of stitching.
These characteristics of the prior art are overcome in our previously filed, commonly owned U.S. Pat. No. 5,270,939, issued on Dec. 14, 1993, and entitled METHOD FOR MODIFYING EMBROIDERY DESIGN PROGRAMS, the contents of which are incorporated herein by reference, in its entirety. As described therein, the low-level stitch-by--stitch numerical control codes for embroidery character representations may be converted into a condensed, high-level, data outline format ("outline format") which may be edited, modified and converted back to stitch data. The outline data files may have any convenient format. Generally, these files contain point data, which, when connected, create a frame of the embroidery character. If desired, the outline data may also contain stitch control data, such as stitch density, or pull compensation. The prior art methods currently available do not permit a user to convert an embroidery design program into such an outline format which can be easily edited and manipulated.
Childs et al, U.S. Pat. No. 4,352,334 discloses a prior art system for stitching along an arc employing the traditional storage of low-level stitch data, and requires that all. of this stitch data be loaded and retained in memory before any transposition of the stitch data to the arced orientation may occur. Furthermore, Childs does not modify the shape of the embroidery character itself, but merely the orientation of the character. These disadvantages inhibit the provision of an efficient system for manipulation of embroidery designs, such as for providing bridge lettering.
While conventional embroidery stitching systems, such as Childs et al, can place letters on straight lines, either horizontally, vertically, at an angle, or on arcs or circles, none of the prior embroidery systems can efficiently provide true bridge lettering for embroidery patterns. This is so even though bridge lettering systems are commonly known for silkscreening or in typography. For example, in silkscreening, it is necessary only to generate the exterior line segments of the lettering. These segments must include the necessary curvature of the bridge. Embroidery requires more than just the outline data to do bridge lettering. Embroidered letters are typically made from outline data which comprises both a description of the outline of the lettering, as well as stitch instructions.
Thus, it is desirable to have a system which can be used to create embroidery designs, and modify the designs in different ways in an efficient and timely manner. It is also desirable that the system may operate on outline data to obviate the need for converting large numbers of stitch point data when changing the orientation of the embroidery design as is required when low-level stitch data is employed. It is also desirable that the system should be able to generate the necessary stitch codes for driving the different types of embroidery machines to stitch the created design.